Ξc−Ξc′ mixing from lattice QCD

Abstract

In heavy quark limit, the lowest-lying charmed baryons with two light quarks can form an SU(3) triplet and sextet. The Ξc in the SU(3) triplet and Ξc′ in the sextet have the same JPC quantum number and can mix due to the finite charm quark mass and the fact the strange quark is heavier than the up/down quark. We explore the Ξc–Ξc′ mixing by calculating the two-point correlation functions of the Ξc and Ξc′ baryons from lattice QCD. Based on the lattice data, we adopt two independent methods to determine the mixing angle between Ξc and Ξc′. After making the chiral and continuum extrapolation, it is found that the mixing angle θ is 1.2∘±0.1∘, which seems insufficient to account for the large SU(3) symmetry breaking effects found in weak decays of charmed baryons.